As the art of restraining the discharge of HC at the time of start of a port injection type internal combustion engine, an art is known, which is described in Japanese Patent Laid-Open No. 2008-291686. The art described in Japanese Patent Laid-Open No. 2008-291686 sets the closing timing of the exhaust valve at an advance side from the intake top dead center by operating the variable valve timing mechanism, opens the intake valve in proximity to the intake top dead center after the exhaust valve is closed, and performs intake-asynchronous injection prior to opening of the intake valve. By closing the exhaust valve in the timing earlier at an advance side from the intake top dead center, part of the combustion gas can be confined in the combustion chamber. Subsequently, a fuel is injected into the port by intake-asynchronous injection, and thereafter, the intake valve is opened in proximity to the intake top dead center, whereby vaporization of the fuel can be promoted by the combustion gas which is blown back to the intake port from the inside of the combustion chamber.
However, the art described in Japanese Patent Laid-Open No. 2008-291686 is still susceptible to improvement. At the first cycle of start of each cylinder, that is, before initial explosion, the gas which is blown back to the intake port does not contain combustion gas. Further, the negative pressure of the intake port at the time of start of an internal combustion engine is small, and especially in the case before explosion, the intake port has substantially atmospheric pressure. Accordingly, the pressure difference between the intake port and the combustion chamber is small when the intake vale is opened, and the amount of the gas itself which is blown back is not large. Accordingly, in regard with the first cycle of start, the fuel for initial explosion which is injected to the intake port is unlikely to be sufficiently vaporized.